Mechanical test systems are used to determine various characteristics of materials. For example tensile strength, amongst other parameters, is tested with systems such as the ElectroForce® 3200 Test Instrument from Bose Corporation. A linear electromagnetic motor is used to apply the load to the material. A sensor (e.g. a load cell) measures an output of the system while the material is under the load and provides a feedback signal, which is used in controlling operation of the motor. Relatively high-frequency resonances and phase delay introduced into the sensor by the system, the material being tested, or inherent in the sensor itself, can cause the feedback signal to negatively impact the operation of the motor. Furthermore, motions of the system can induce errors in the load measurement. Methods have been developed (e.g. American Society for Testing and Materials, ASTM E467) for the assessment and correction of these errors, however, these methods can be time consuming to implement. In some cases, they may not be practical or even possible (e.g. placing strain gauges on a biological sample).
U.S. Pat. No. 6,940,248 discloses a motion controller including a combining network having an acceleration input for receiving an acceleration signal representative of acceleration of a movable element and a position input for receiving a position signal representative of position of the movable element and an output for providing an inferred position signal representative of an inferred position of the movable element. The network includes a first signal processor for processing the acceleration signal to provide modified acceleration signal, a second signal processor for processing the position signal to provide a modified position signal and a combiner for combining the modified acceleration signal with the modified position signal to provide the inferred position signal. This system uses a combination of position detection and acceleration to generate a position source but does not teach a solution to reducing the error in a force measurement due to motion of the test system, high-frequency resonances or phase delay introduced into the sensor. Thus, there remains a requirement to reduce these error sources in an efficient manner.